Code example: Custom property plug-in

Create a basic custom property plug-in

1. In Microsoft Visual Studio, create a new project. Select Class Library(.Net framework) as template and enter a name for your project.

2. Add Tekla API assemblies to your project as references.

3. Rename Class1.cs to CustomProperty.cs (this could be a more specific name). Edit CustomProperty.cs:

   • Add assemblies needed:

     using System.ComponentModel.Composition; // only 2024 and older versions
     using Tekla.Structures.Model;
     using Tekla.Structures.CustomPropertyPlugin;

     In TeklaStructures 2024 and older versions Custom property functionality is using Managed Extensibility Framework (MEF) for loading custom property assemblies, therefore a reference to System.ComponentModel.Composition assembly is needed in the project.

     Starting in TeklaStructures 2025 loading custom property assemblies only need Open API libraries.

   • Define needed metadata for custom property: 

     // only 2024 and older versions
     [Export(typeof(ICustomPropertyPlugin))]
     [ExportMetadata("CustomProperty", "CUSTOM.NAME_OF_THE_PROPERTY")]
     
     // available from TeklaStructures 2025
     [CustomPropertyPlugin("CUSTOM.NAME_OF_THE_PROPERTY")]

   • Implement the ICustomPropertyPlugin interface: 

     //Methods in the interface are passing object ID as argument. 
     //Identifier of the object can be constructed using the ID in order to utilize 
     //the functionality in Tekla.Structures.Model assembly.
     
     public class CustomPropertyTest : ICustomPropertyPlugin 
     { 
         //Return custom property int value for object.
         public int GetIntegerProperty(int objectId) 
         { 
             return -1 * objectId; 
         } 
      
         //Return string value for object.
         public string GetStringProperty(int objectId) 
         { 
             return "Hello " + objectId.ToString(); 
         } 
      
         //Return double value for object.
         public double GetDoubleProperty(int objectId) 
         { 
             return (double)(-1 * objectId); 
         }
     }

Test example application

1. In Microsoft Visual Studio, open and build project CustomProperty.cs to create the .dll file. The file is located at \Examples\CustomProperties\CustomPropertyTest.
2. Copy the custom property .dll file to \environments\common\extensions\custom\properties\. (Create the \custom\properties\ folder if needed, inside the location where your common environment is located after installing Tekla Structures).
3. Check if the plug-in loads:
   • Open a model in Tekla Structures, on the File menu, click Logs and select session history log. From the list you can see if your plug-in has loaded.